[xubuntu] Difference between Xubuntu and Ubuntu with XFCE

http://ubuntuforums.org –
As the title says, a very simple question;
What is the difference between a Xubuntu and an Ubuntu with XFCE (Xubuntu-Desktop packages) installed?
Is there only a difference in installed packages and default applications, or are there other differences as well?
And would there be any reason to install Ubuntu with the Xubuntu-Desktop packages rather than Xubuntu itself?
Thanks.
(Hardware)